I would imagine that many people feel that way about themselves, especially on here when there is a lot of self hate and negative views and opinions about ourselves. We are our own worst enemy sometimes.

If you are too aware of potentially people not liking you, then it can become a self fullfilling prophecy, which can be even harder to face.

Have you tried building your self esteem? Maybe try asking those who know you will what your good qualities are, why they like you, etc, and also try to keep things rational in your head with 'I may think X, but others think Y' to try and remind yourself that people view you differently from how you view yourself.